Feasibility of Mg/Br-Codoped Formamidinium Tin Iodide for Flexible Perovskite Solar Cells

This work presents the properties of Mg/Br-codoped formamidinium tin iodide, which are obtained from the density functional theory (DFT), and the photovoltaic characteristics of the solar cells with the Mg/Br-codoped formamidinium tin iodide absorber layers, which are investigated by a drift-diffusion model including the tunneling mechanism. The elastic, electronic, and optical properties of Mg/Br-codoped formamidinium tin iodide attained from the DFT are promising for flexible perovskite solar cells (FPSCs). The predicted properties of the perovskite materials as well as the calculated current density–voltage characteristics and external quantum efficiency of the FPSCs are discussed and in agreement with both theoretical and experimental data in the literature. The Nyquist and Bode phase plots from the impedance spectroscopy simulation of the Mg/Br-codoped formamidinium tin iodide FPSCs indicate the long carrier lifetimes and the small accumulation of photogenerated carriers in the absorber layers, resulting in their high efficiency.